The AAVSO was formed in 1911 as a group of US-based amateur observers obtaining data in support of professional astronomy projects. Now, it has evolved into an International Organization with members and observers from both the professional and non-professional astronomical community, contributing photometry to a public photometric database of about 22,000 variable objects, and using it for research projects. As such, the AAVSO’s main claim to fame is that it successfully engages backyard Astronomers, educators, students and professional astronomers in astronomical research. I will present the main aspects of the association and how it has evolved with time to become a premium resource for variable star researchers worldwide.

As improvements to instrumentation enable the detection of progressively smaller photometric signals, it is important to consider the observability of phenomena that have thus far been below detection thresholds. In this talk, I will explore the occurrence and detectability of planet-planet occultations (PPOs) in TRAPPIST-1 and other nearby exoplanet systems. PPOs are events during which an exoplanet occults the disk of another planet in the same system, imparting a small photometric signal as its thermal or reflected light is temporarily blocked. When marginalizing over the uncertainties on all orbital parameters, I find that of order one PPO occurs per day in TRAPPIST-1, with an expected 40 occultations of TRAPPIST-1b and TRAPPIST-1c per year with the potential for detection with the upcoming James Webb Space Telescope (JWST). I will show how the detection of PPOs can be used to break transit timing variation degeneracies, imposing strong constraints on the eccentricities and masses of the planets, as well as to constrain the longitudes of nodes and thus the complete three-dimensional structure of the system. I will also show how photodynamical modeling of these events can be used to reveal a planet’s day/night temperature contrast and construct crude two-dimensional surface maps.